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Gas-generator Cycle
The gas-generator cycle is a power cycle of a pumped liquid bipropellant rocket engine. Part of the unburned propellant is burned in a gas generator (or preburner) and the resulting hot gas is used to power the propellant pumps before being exhausted overboard, and lost. Because of this loss, this type of engine is termed open cycle. Usage Gas-generator combustion engines include the following: * Vulcain, HM7B *Merlin *RS-68 *RS-27A *J-2X * F-1 *RD-107 * CE-20 * Rocket launch systems that use gas-generator combustion engines: *Ariane 5 *Falcon 9, Falcon Heavy *Delta IV *Saturn V *Soyuz * Geosynchronous Satellite Launch Vehicle III *Long March 3B, Long March 2F *Rocket Lab Neutron *Miura 5 See also * Combustion tap-off cycle * Expander cycle * Pressure-fed engine * Rocket engine A rocket engine uses stored rocket propellants as the reaction mass for forming a high-speed propulsive jet of fluid, usually high-temperature gas. Rocket engines are reaction engines, producin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gas Generator Rocket Cycle
Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or compound molecules made from a variety of atoms (e.g. carbon dioxide). A gas mixture, such as air, contains a variety of pure gases. What distinguishes a gas from liquids and solids is the vast separation of the individual gas particles. This separation usually makes a colourless gas invisible to the human observer. The gaseous state of matter occurs between the liquid and plasma states, the latter of which provides the upper temperature boundary for gases. Bounding the lower end of the temperature scale lie degenerative quantum gases which are gaining increasing attention. High-density atomic gases super-cooled to very low temperatures are classified by their statistical behavior as either Bose gases or Fermi gases. For a comprehensive list ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delta IV
Delta IV is a group of five expendable launch systems in the Delta (rocket family), Delta rocket family introduced in the early 2000s. Originally designed by Boeing's Defense, Space and Security division for the National Security Space Launch, Evolved Expendable Launch Vehicle (EELV) program, the Delta IV became a United Launch Alliance (ULA) product in 2006. The Delta IV is primarily a launch vehicle for United States Air Force (USAF) military payloads, but has also been used to launch a number of United States government non-military payloads and a single commercial satellite. The Delta IV originally had two main versions which allowed the family to cover a range of payload sizes and masses: the retired Medium (which had four configurations) and Delta IV Heavy, Heavy. As of 2019, only the Heavy remains active, with payloads that would previously fly on Medium moving to either the existing Atlas V or the forthcoming Vulcan (rocket), Vulcan. Retirement of the Delta IV is antici ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Combustion
Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion does not always result in fire, because a flame is only visible when substances undergoing combustion vaporize, but when it does, a flame is a characteristic indicator of the reaction. While the activation energy must be overcome to initiate combustion (e.g., using a lit match to light a fire), the heat from a flame may provide enough energy to make the reaction self-sustaining. Combustion is often a complicated sequence of elementary radical reactions. Solid fuels, such as wood and coal, first undergo endothermic pyrolysis to produce gaseous fuels whose combustion then supplies the heat required to produce more of them. Combustion is often hot enough that incandescent light in the form of either glowing or a flame is produced. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Staged Combustion Cycle
The staged combustion cycle (sometimes known as topping cycle, preburner cycle, or closed cycle) is a power cycle of a bipropellant rocket engine. In the staged combustion cycle, propellant flows through multiple combustion chambers, and is thus combusted in stages. The main advantage relative to other rocket engine power cycles is high fuel efficiency, measured through specific impulse, while its main disadvantage is engineering complexity. Typically, propellant flows through two kinds of combustion chambers; the first called preburner and the second called main combustion chamber. In the preburner, a small portion of propellant, usually fuel-rich, is partly combusted, and the increasing volume flow is used to drive the turbopumps that feed the engine with propellant. The gas is then injected into the main combustion chamber and combusted completely with the other propellant to produce thrust. Tradeoffs The main advantage is fuel efficiency due to all of the propellant flo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rocket Engine
A rocket engine uses stored rocket propellants as the reaction mass for forming a high-speed propulsive jet of fluid, usually high-temperature gas. Rocket engines are reaction engines, producing thrust by ejecting mass rearward, in accordance with Newton's third law. Most rocket engines use the combustion of reactive chemicals to supply the necessary energy, but non-combusting forms such as cold gas thrusters and nuclear thermal rockets also exist. Vehicles propelled by rocket engines are commonly called rockets. Rocket vehicles carry their own oxidiser, unlike most combustion engines, so rocket engines can be used in a vacuum to propel spacecraft and ballistic missiles. Compared to other types of jet engine, rocket engines are the lightest and have the highest thrust, but are the least propellant-efficient (they have the lowest specific impulse). The ideal exhaust is hydrogen, the lightest of all elements, but chemical rockets produce a mix of heavier species, reducing the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pressure-fed Engine
The pressure-fed engine is a class of rocket engine designs. A separate gas supply, usually helium, pressurizes the propellant tanks to force fuel and oxidizer to the combustion chamber. To maintain adequate flow, the tank pressures must exceed the combustion chamber pressure. Pressure fed engines have simple plumbing and have no need for complex and occasionally unreliable turbopumps. A typical startup procedure begins with opening a valve, often a one-shot pyrotechnic device, to allow the pressurizing gas to flow through check valves into the propellant tanks. Then the propellant valves in the engine itself are opened. If the fuel and oxidizer are hypergolic, they burn on contact; non-hypergolic fuels require an igniter. Multiple burns can be conducted by merely opening and closing the propellant valves as needed, if the pressurization system also has activating valves. They can be operated electrically, or by gas pressure controlled by smaller electrically operated valves. Care ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Expander Cycle
The expander cycle is a power cycle of a bipropellant rocket engine. In this cycle, the fuel is used to cool the engine's combustion chamber, picking up heat and changing phase. The now heated and gaseous fuel then powers the turbine that drives the engine's fuel and oxidizer pumps before being injected into the combustion chamber and burned. Because of the necessary phase change, the expander cycle is thrust limited by the square–cube law. When a bell-shaped nozzle is scaled, the nozzle surface area with which to heat the fuel increases as the square of the radius, but the volume of fuel to be heated increases as the cube of the radius. Thus beyond approximately 300 kN (70,000 lbf) of thrust, there is no longer enough nozzle area to heat enough fuel to drive the turbines and hence the fuel pumps. Higher thrust levels can be achieved using a bypass expander cycle where a portion of the fuel bypasses the turbine and or thrust chamber cooling passages and goes directly to the ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Combustion Tap-off Cycle
The combustion tap-off cycle is a power cycle of a bipropellant rocket engine. The cycle takes a small portion of hot exhaust gas from the rocket engine's combustion chamber and routes it through turbopump turbines to pump fuel before being exhausted (similar to the gas-generator cycle). Since fuel is exhausted, the tap-off cycle is considered an open-cycle engine. The cycle is comparable to a gas-generator cycle engine with turbines driven by main combustion chamber exhaust rather than a separate gas generator or preburner. The J-2S rocket engine, a cancelled engine developed by NASA, used the combustion tap-off cycle and was first successfully tested in 1969. By 2013, Blue Origin, with their New Shepard launch vehicle, had successfully flight-tested the BE-3 engine using a tap-off cycle. According to Blue Origin, the cycle is particularly suited to human spaceflight due to its simplicity, with only one combustion chamber and a less stressful engine shutdown process. However, e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miura 5
Miura 5 is a two-stage European orbital recoverable launch vehicle of the Spanish company PLD Space currently under development. Miura 5 will be 24.9 m long, capable of inserting 900 kg of payload into a low Earth orbit (LEO), featuring an optional kick stage that can circularize the orbits of satellites. All stages are planned to be liquid-propelled. The launch vehicle was previously called ''Arion 2'' but in 2018 PLD Space changed its name. Design The two stages (expandable to 3) of the Miura 5 are planned to use liquid fuel and are designed to reuse most of the technology developed for Miura 1, being the new engine and propellant tanks. The first stage is planned to be reusable through the combined use of its engines and parachutes for retrieval. The Miura 5 will use a TEPREL-C turbopump engine, unlike previous versions which use a pressurized tank cycle. A lift capacity of 150 kilograms was originally envisioned, but in 2018 lift capacity was doubled after a 10-m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rocket Lab Neutron
Neutron is a medium-lift two-stage launch vehicle under development by Rocket Lab. Announced on 1 March 2021, the vehicle is being designed to be capable of delivering a payload of to low Earth orbit in a partially reusable configuration, and will focus on the growing megaconstellation satellite delivery market. The vehicle is expected to be operational sometime in 2024. It uses LOX and liquid methane propellant on both stages of the vehicle. Design An earlier design of Neutron, featured at the initial unveil in March 2021, featured a rocket tall with a -diameter payload fairing. Rocket Lab stated that they intended for the first stage of the vehicle to be reusable, with landings planned on a floating landing platform downrange in the Atlantic Ocean. On 2 December 2021, Rocket Lab unveiled a revised design for Neutron, featuring a tapered shape with a maximum diameter of . Rocket Lab abandoned plans for landing Neutron on a floating platform, instead opting for a return- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long March 2F
The Long March 2F ( ''Changzheng 2F''), also known as the CZ-2F, LM-2F and Shenjian (, "Divine Arrow"), is a Chinese orbital carrier rocket, part of the Long March 2 rocket family. Designed to launch crewed Shenzhou spacecraft, the Long March 2F is a human-rated two-stage version of the Long March 2E rocket, which in turn was based on the Long March 2C launch vehicle. It is launched from complex SLS at the Jiuquan Satellite Launch Center. The Long March 2F made its maiden flight on 19 November 1999, with the Shenzhou 1 spacecraft. After the flight of Shenzhou 3, CPC General Secretary and President Jiang Zemin named the rocket "Shenjian" meaning "Divine Arrow". On 29 December 2002, a Long March 2F launched Shenzhou 4 for a final uncrewed test of the Shenzhou spacecraft for the upcoming flight of the first crewed mission. Until then, all missions were uncrewed. On 15 October 2003, a Long March 2F launched Shenzhou 5, China's maiden crewed mission and achieved its first human spa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long March 3B
The Long March 3B (, ''Chang Zheng 3B''), also known as the CZ-3B and LM-3B, is a Chinese orbital launch vehicle. Introduced in 1996, it is launched from Launch Area 2 and 3 at the Xichang Satellite Launch Center in Sichuan. A three-stage rocket with four strap-on liquid rocket boosters, it is currently the second most powerful member of the Long March (rocket family), Long March rocket family after the Long March 5 and the heaviest of the Long March 3 rocket family, and is mainly used to place communications satellites into geosynchronous orbits. An enhanced version, the Long March 3B/E or G2, was introduced in 2007 to increase the rocket's geostationary transfer orbit (GTO) cargo capacity and lift heavier geosynchronous orbit (GEO) communications satellites. The Long March 3B also served as the basis for the medium-capacity Long March 3C, which was first launched in 2008. , the Long March 3B, 3B/E and 3B/G5 have conducted 82 successful launches, plus 2 failures and 2 partial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
